In an interview with Sky News, Dragana Haines said that her husband's captors were "cowards".

"They consider themselves brave, but that's not bravery. It's a cowardly act to behead someone who has his hands tied behind his back, who is kneeling.

"You are a coward if you are going to behead someone who is helpless. You're not even a human being. You must be a monster to do something like that."

Mrs Haines, who met Mr Haines in post-war Yugoslavia whilst working as a translator for the Organisation for Security and Co-operation in Europe (OSCE), revealed her difficulty in not knowing what had happened to her husband when he was kidnapped in March 2013. He had been working for a French aid agency and had considerable experience working in conflict zones.

"Every day was a challenge. Waking up in the morning and thinking OK should I be hopeful? Will it be a day when they will call me, or he will call me and say 'OK I'm free, I'm coming back'?

"Or will it be a day when they will call me and say something bad has happened?"

Speaking from her home in Croatia, Mrs Haines recalled seeing her husband's face in the video for the first time: "I just saw the part when he was talking. I never found enough strength to see the rest of the video. I don't want to see it."

Mrs Haines revealed her struggle in trying to hide her emotional difficulties from her 4-year-old daughter:

"I was trying to go to my room so she wouldn't see me crying, but of course she heard me.

"After a few times she realised that as soon as I start speaking in English to someone on the phone, that it was Uncle Mike (Mr Haines' brother), she would run and bring me handkerchiefs and say 'Mum don't be sad, please don't cry', because even she understood that something wrong was going on."

She ended the interview, saying: "David gave sense to my life. He made it something different, he changed it – and now Athea is my reason to go on. David would want me to be strong, for our daughter."